Variable-speed direct-current generator.



A. RICHTER. VARIABLE SPEED DIRECT CURRENT GENERATOR. APPLICATION FILED00122, 1913.

Patented Oct. 27, 1914.

ALFRED RICHTER, OF CHICAGO, ILLINOIS.

VARIABLE-SPEED DIRECT-CURRENT GENERATOR.

Specification of Letters Patent.

Patented Oct. 27, 191 1.

Application filed October 22, 1913. Serial No. 796,597.

To all whom it may concern Be it known that I, ALFRED RICHTER, a citizenof the United States, residing at Chicago, in the county of Cook andState of Illinois, have invented certain new and useful Improvements inVariable-Speed Direct-Current Generators, of which the following is afull, clear, and exact description.

This invention relates to improvements in direct-current generators usedon motorcycles, automobiles or motor boats, for the purpose of keepingthe storage battery fully charged.

The principal objects of the invention are to provide a system ofregulation which will be adapted for use on extremely small generators,as used for instance on motorcycles; to provide a system of regulationwhich will be effective at the maximum speeds to which the generatorwill be subjected; to provide a system of regulation whichwill notinterfere with or lower the output of the generator when operated atextremely low speeds; to provide a system which will in all casesprotect the battery from overcharge, and also protect the generator fromoverload; to provide means for disconnecting the battery from thegenerator when the generator stops running, and to connect the batteryto the generator when the latter reaches a definite speed; to provide asystem which will be adapted for use with any kind of generator; toprovide a system which can be cheaply constructed and easily maintained,and which will not readily get out of order; and in general to providean improved system and apparatus of the ch aracter referred to.

Referring to the drawings,-Figure 1 is a diagrammatic view showing mysystem applied to a direct-current generator of the electromagnetic typewith field windings on one pole only; Fig. 2 is a side elevation of therelay mechanism; Fig. 3 is a plan of Fig. 2; and Fig. 4 is a sideelevation of Fig. 2.

Similar figures refer to similar parts throughout the several views.

Referring to Fig. 2, 1 is an iron core upon which is wound a coarse-wirewinding S. At the lower end of the core is an iron plate 2 fastened tothe core 1 by means of a screw 3. The upper end of the core 1 issimilarly provided with an iron plate 4:, on the outer end of which isfastened a small core 5. This small core 5 is provided with a shuntwinding P, and on the end of this small core5is fixed a small ironprojection 6. The ends of the iron pieces 2 and 6 thus form two polesfor the cores 1 and 5. The armature 7 is adapted to be normally heldaway from the poles 2 and 6 by means of its supporting spring 8, towhich it is attached by means of screws 9. The spring 8 is supported onabrass extension piece 10, which is attached by a screw 11 to the topplate 4. The spring 8 is rigidly connected to the piece 10 by means of ascrew 12. The armature 7 is provided with a contact 13 which engageswith the contact screw 11 when the armature is attracted by the poles 2and 6, the spring 8 normally holding it out of contact therewith. Thescrew 14 is set in an angle piece 15 which is attached to and insulatedfrom the heel plate 2: The other end of the top piece 4 1s notched outwide enough to admit the armature 16, which is pivoted between the forksthus formed, the pivot being shown at 17. The armature 16 is long enoughto be attracted by the adjacent end of the heel iron 2 when the core 1is energized sufficiently. On the back of the armature is fastened, bymeans of a screw 18, a plate 19 which carries a contact 20. The contact20 normally makes contact with the contactscrew 21, the latter beingsupported on a bracket 22. The bracket 22 is rigidly attached to thefiber base 23 by means of a screw not shown, the fiber base also beingrigidly attached to the heel iron 2. The contact 20 is pressed upagainst the screw 21 positively by means of a spring 21, which isfastened onto the back of the armature 16. The free end of the spring 24can be varied in tension by means of an adjusting screw 25, against theend of which it presses, the screw 25 being mounted in the bracket 10.

It will be seen that when the core 1 is energized by means of thewinding S, the armatures 7 and 16 will both be attracted to a greater orless extent depending on the current flowing through the winding S. Whenthe winding P is energized, however, its principal effect is to attractthe armature 7, which is situated adjacent to the end of the winding,the winding P not having much effect on the armature 16 owing to thelarge amount of magnetic leakage, and also owing to the fact that thecore 1 acts as a shunt circuit for the magnetic lines of force.

Referring now to Fig. 1, 26 represents the.

field magnet of a direct-current generator G of the electromagnetictype, the armature being shown at 27. The dynamo is provided with theusual brushes 28 and-29, commutator 30, pole shoes 31 and 32, thewinding being shown on the single core 33. The field winding consists ofa fine-wire Winding 34 and a series winding 35: The latter is connectedso that when energized by current flowing from the generator in adirection to charge the battery it will tend to neutralize the effect ofthe winding 34, and thus lower the voltage and reduce the output of thegenerator. One end of the winding 35 is connected to the winding 34 at36, and also to the contact 21, hereinbefo-re described, by means of thewire, 37 this contact also being connected to the negative pole of thebattery 38 by means of a wire 39. The other end of the series winding 35is connected with contact 20 and to the brush 29 by means of a wire 40.The brush 28 is connected to the shunt winding P and the series windingS of the relay mechanism by a conductor 41, and to the end of the fieldwinding 34 by a conductor 42. The other end of the shunt winding P isconnected to the conductor 37. The free end of the series winding Sterminates at the contact 14, normally not in engagement with thecontact 13, the latter being connected to the positive pole of thestorage battery 38 by means of a conductor 43.

The operation of the system and apparatus will now be described. Thegenerator G is positively driven by means of a belt, chain, gears orother approved method, from the crank shaft of the engine of themotorcycle or automobile. It will thus be seen that it will run atWidely varying rates of speed, particularly in the case of a gasolineengine, for which my system is especially adapted. Under ordinaryconditions, when the generator commences to run, the contacts 20 and 21being closed, the series winding 35 is inoperative and the shunt winding34 is at its full efficiency. The generator therefore begins to build upits voltage quite rapidly. As soon as the voltage of the generatorreaches a certain amount, usually in the neighborhood of six and a halfvolts, the shunt winding P of the relay mechanism is suflicientlyenergized to attract the armature 7 and close the contacts 13 and 14.The circuit for this can be traced from the brush 29, conductor 40,contacts 20 and 21, conductor 37, windin P conductor 41, to the brush28, the shunt eld winding 34 being electrically in shunt with thewinding P and energized by the same set of connections. As the generatorspeed rises, the voltage increases and current commences to flow throughthe battery 38 through the following circuit: from the brush 28 by wayof the conductor 41 to the series windings S of the relay mechanism,through contacts 14 and 13, conductor 43, to the positive pole of thebattery, and from the negative pole back to the brush 29 by way of theconductor 39, contacts 21, 20, and conductor 40. This condition prevailsas long as the generator speed and voltage are below a certain amount.When the speed of the generator rises still further, however, thevoltage also rising with it, a large amount of current will tend to passinto the battery. The contact screw 25, however, is adjusted so thatwhen a definite amount of current passes through series winding S, thearmature 16 will be attracted against the tension of the spring 24, andwill open the contacts 20 and 21. When this occurs, current will notflow through the conductor 40, but will be forced through the seriesfield winding 35, which, as before stated, is connected so as toneutralize the effect of the shunt winding 34. As a result, thegenerator voltage will fall rapidly, and the charging current will becorrespondingly reduced to a safe figure. The armature 16 will then fallback and close the contacts 20 and 21, short-circuiting the buckingwinding 35, and the generator voltage will again build up. Excesscurrent will flow through the winding S, and again open the contacts 20and 21; this cycle of operations being repeated as long as the generatorspeed is high enough. In practice, after the generator speed reaches acertain figure, the contacts 20 and 21 are continually opening and 010sing. When the generator speed falls below a certain amount, its voltagewill be too low to charge the battery, and current will tend to flowfrom the battery to the generator. When this occurs, however, thiscurrent,

which must of necessity pass through the series winding S of the relaymechanism, will operate to neutralize the effect of the shunt winding P,the armature 7 will be re: leased, open the contacts 13 and 14, and thebattery will be disconnected. It will be seen that'the shunt winding Pof the relay mechanism is not connected permanently across the brushesof the dynamo, but ata point electrically between the series winding Sand one brush on one side of the line, and between the battery and theregulating contacts on the other side of the line, and is therefore notafl'ected by changes in the rela-' tion of the regulating contacts orfluctuations of current in the series winding 35.

It will readily'be seen that the use of my system is not limited to agenerator of the electromagnetic type. A magneto-type generator with asingle bucking winding could be used with equal facility. It is obviousthat my apparatus could also be used with direct-current generators withany number of poles or field windings.

I do not limit myself to the details shown except in so far as they aremade the subject of specific language in the appended claims.

I claim: v a

1. In a battery-chargingsystem, the combination of a storage battery, adirect-current generator provided with a shunt field winding, and aseries field winding operating to reduce the field of the generator whencurrent passes through it in a direction to charge the battery, contactsnormally shortcircuitin said series winding, and .means for opening saidcontacts controlled by the charging current, the shunt winding ofthegenerator being connected electrically between the battery and theshort-circuiting contacts. a

2. In a battery-charging system the combination of a storage battery, adirect-current generator provided with a series field winding operatingto reduce the field of the generator when current passes through it in adirection to charge the battery, contacts normall short-circuiting saidwinding, means or openingv said contacts controlled by the chargingcurrent, a shunt field wind-- ing connected electrically between thebattery and the shortci rcu1ting contacts, contacts efi'ecting closureof the battery circuit, and a shunt relay connected across said shuntfield winding controlling said battery contacts.

3. In a battery-charging system, the combination with a storage battery,of a directcurrent enerator provided with a series field win ingoperatin to reduce the field of the generator w en current passesthrough it in a direction to charge the battery, contacts normallyshort-circuiting said winding, means for opening said contactscontrolled by the charging current, a shunt field winding connectedelectrically between the battery and the short-circuiting contacts, ashunt relay connected across said shunt field, contacts controlled bysaid shunt relay for e'fit'e cting closure of the battery circuit, andmeans for opening said contacts controlled by the dischar e current.

In witness whereo I hereunto subscribe my name this 16th day of October,A. 1)., 1913.

ALFRED RICHTER.

Witnesses: I

SADIE M. RYAN, JAMES R. OFFIELD.

